Transducers known as ribbon tweeters have been known in the past. They have been marginally useful for several reasons.
Such ribbon tweeters have been extremely large and bulky for the output obtained; have had objectionable beaming characteristics so that their output can be heard in only isolated locations; their impedance has been so low that expensive transformers have been required to match the transducer impedance to the amplifier impedance; and finally, only minimal output from such ribbon tweeters has been possible.
Accordingly, use of such ribbon tweeters has not proved effective, and use of such ribbon tweeters has not become widespread.